Distributor shield assembly



Sept. 26, 1944. HALLETT 2,358,971

' I DISTRIBUTOR SHIELD ASSEMBLY Filed June 15, 1942 ALFEED 53444577,

/ IN! '[i'Y TOR.

Patented Sept. 26, 1944 UNITED STATES PATENT orrics DISTRIBUTOR SHIELDASSEMBLY Alfred Hallett, Los Angeles, Calif., assignor to HallettManufacturing Company, Inglewood, Calif., a copartnership ApplicationJune 1 5, 1942, Serial No. 447,075

. January 21, 1942, for Shielding for electrical sys- 4 Claims.

This invention relates to the shielding and protection of electricalsystems for internal combustion engines.

Free electrical radiations from ignition systems of internal combustionengines used in proximity to radio receiving apparatus are picked up insuch apparatus and interfere with reception. This is a serious factor inthe operation of airplanes, motorboats, submarines, military landvehicles, and all other types of mobile transportation, as well as instationary installations, employing radio equipment.

Certain forms of shielding have heretofore been employed for the purposeof grounding electrical radiations but so far as I am aware no attempthas been made previous to my present invention to provide a shieldingfor the distributor assembly of an ignition system which is one of themost active Sources of interfering radiation.

Moreover, it has been found in practice that if the distributor assemblyof an ignition system is exposed to the elements, particularly whenunder heavy duty and adverse weather or operating conditions, moisture,water, oil and gas may be deposited on the distributor and the terminalsconnecting therewith unless protected by moisture-proof and water-proofenclosures. In asmuch as cables must lead to such distributor assemblythe protective means should include the regions where the cables enterthe protective housing.

It is therefore an object of my invention to provide an electricalshielding for a distributor assembly which combines the function 'ofphysical protection to the elements of the assembly against weather andother adverse operating conditions which normall contribute to failureof the distributor, deterioration of insulation, connections, etc. It isa further and more specific object of my invention to provide a metallicshielding for the distributor assembly of an ignition system whichcompletely encloses and grounds the same, avoiding openings or cracksthrough which electrical radiations might escape, effecting improvedelectrical connections at the terminals, and physical protection of thesystem against external conditions described.

A still further object of my invention is to pro-= vide a distributorshield assembly of the character described which is adaptable to theconventional distributor installation and may be combined therewith witha minimum, if any, alteration.

These and other objects of my invention will be made more apparent froma consideration of the full description and drawing.

This application is a continuation in part of my copending applicationSerial No. 427,621, filed tems.

In the drawings:

Figure 1 is a vertical sectional view of my shielding applied to aconventional distributor. The line l-l in Figur 2 illustrates thesection upon which Figure 1 is taken.

Figure 2 is a cross-sectional view of the same taken on the line 2-2 ofFigure 1.

Figure 3 is a fragmentary vertical section taken on the line 3-3 ofFigure 1.

Figure 4 is a fragmentary enlarged vertical section taken on the line 44of Figure 2.

My distributor shield assembl comprises essentially a standarddistributor in having a head H centered upon a standard flanged base l2and including terminal posts 13 for electrical connections H. Thedetails of the distributor itself except as hereinafter described arenot part of my invention.

The distributor is mounted within an inverted substantially cup-shapedmetallic housing 15 through which terminals 58 pass and which terminalsare a part of the connections I4.

The housing i5 is seated upon a metallic mounting ring I! which in turnis bolted upon a horizontal flange N3 of the base 12. The base I2 ismetal and grounded by any conventional means of mounting to the engineor frame not illustrated.

The housing 15 and ring ll are of sufficiently high conductive metal, toground any electrical radiations.

4 The ring I! is of particularly novel configuration. The inner diameterof said ring is adapted to snugly encircle the upstanding cylindricalflange 2| of the base !2, and is formed with a shallow annular seat 22upon which the distributor head H is adapted to rest. The ring is alsoformed with a plurality of bosses 23 which are tapped and threaded toaccommodate cap screws 24 by which the ring ll i securely bolted uponthe flange it of the base 12. Additional bosses 25 are formed on thering at suitable Spacing from. oppositely disposed bosses 23, and thebosses 25 and their companion bosses 23 are tapped and threaded as at 26to accommodate set screws 21. These screws are formed with shoulders 28enabling the screws to be tightened down upon the bosses 23 and 25; andthe clamping screw 21 are adapted to retain bow springs 29 which engagebosses 30 of conventional design formed on the distributor head I! forretaining the head in correct position. Auxiliary flat bars 3! may besuperimposed upon the springs 29 as a safeguard in the event a springshould break. The screws 21 are preferably formed with fiat sidedelongated heads whereby the screws may be tightened down before thehousing 15 is installed and the latter when in place prevents the screwsfrom turning to loosen.

The ring 11 is also provided with outwardly extending bosses 35 tappedand threaded as at 36 to acco odate cap screws or bolts 31 which passthrough corresponding lugs 38 extending from the housing l5, thus tosecure the housing upon the ring H.

The ring is formed with a recessed seat to in its outer upper facewhereby the housing is is concentrically seated upon the ring. A pin illmay be secured in the ring I! to register with a hole 42 in the boss 38of the ring l! in order that the housing l and the ring l1 may becorrectly registered.

The top of the housing i5 is tapped and threaded as at 5D to accommodatethe terminals I6. Ordinarily the central terminal leads from an ignitioncoil not shown and the concentrically disposed terminals lead to sparkplugs not shown. Each terminal should be located directly over(opposite) its respective post l3. If the central post is elevated asshown, the housing should follow the general contour of the head in suchrespect. These terminals may be of any suitable form and type but arepreferably made in accordance with the disclosure of my aforesaidcopending application Serial No. 427,621. It is desirable that they bewater-proof and moistureproof and that they ground the metal shielding5i of cables 52 to the metallic housing l5.

In general each terminal comprises a collar 53 threaded into the opening50. The collar is provided with an annular ledge 54 upon which seats theshoulder of an insulator 55. The cable passes through a gland 56 and theinsulator. A metal bushing 51 which may be crimped upon the cableshielding 5| or be otherwise secured upon ithas a flanged portionresting upon the upper face of the gland 56 and is forced down by ametal cap 58 threaded upon the upper extension of the collar 53. Thelower end of the cable 52 is provided with any suitable form ofelectrical connection (not illustrated) by which connection is made withthe post 13 of the distributor head. It should be noted that the collar53 is metallic whereby a complete grounding of the metal cable shielding5| is effected with the housing [6 and in turn with the metallic ringsI1 and the metal base 12.

The shielding on the cables illustrated here is herein but is to beaccorded the full scope of the claims so as to embrace any and allequivalent structures.

Having described my invention, what I claim as new and desire to secureby Letters Patent is:

1. A combination comprising: a distributor including a grounded flangedbase and a distributor head adapted to be supported concentricallythereon, a mounting ring of high conductive properties secured upon thebase, means upon the mounting ring adapted to clamp the distributor headupon the said ring, said means including a bow spring engaging astandard boss on the side of the distributor head, and set screwssupporting and tensioning said spring, an inverted cup-shaped housing ofhigh conductive in the form of woven metal sheathing, but a tubularenclosure or other equivalent shielding may be employed.

The terminals are thus locked securely to the housing, insuring anefilcient and satisfactory connection with the distributor, andproviding a moisture-proof and water-proof entry of the cable into thehousing as well as a complete ground-' ing of the metal cable shieldingto the housing.

Thus I have achieved a distributor shield assembly completely enclosedin a structural sense as a protection against water, oil, and dirt andcompletely shielded electrically by a housing which has high conductiveproperties and which is positively connected with the cable shieldingserving to dissipate into the ground all electrical radiation occurringin the unit.

Although I have herein shown and described my invention in what I haveconceived to be the most practical and preferred embodiment, it is,recognized that departures may be made therefrom within the scope of myinvention, which is not to be limited to the details disclosedproperties secured upon the mounting ring with its walls spaced from thedistributor head, and cable terminals leading through said housing tothe distributor head and establishing an electrical connection betweenmetal shielding on said cables and said housing,

2. A combination comprising: a distributor including a grounded flangedbase and a distributor head adapted to be supported concentricallythereon, a mounting ring of high conductive properties secured upon saidbase, means upon said mounting ring adapted to clamp the distributorhead upon said ring, an inverted cup-shaped housing of high conductiveproperties secured upon the mounting ring with its walls spaced from thedistributor head, said mounting ring embodying concentric recesses forcentering the distributor head and housing respectively, and cableterminals leading through said housing to the distributor head andestablishing an electrical connection between metal shielding on saidcables and said housing.

3. A combination comprising: a distributor including a grounded flangedbase and a distributor head adapted to be supported concentricallythereon, a mounting ring of high conductive properties secured upon thebase, means upon the mounting ring adapted to clamp the distributor headupon the said ring, said means including a bow spring engaging astandard boss on the side of the distributor head, and set screwssupporting and tensioning said spring, an inverted cup-shaped housing ofhigh conductive properties secured upon the mounting ring with its wallsspaced from the distributor head, said set screws being formed withfiat-sided, elongated heads which are prevented from turning to unscrewby confinement of the housing wall, and cable terminals leading throughsaid housing to the distributor head and establishing an electricalconnection between metal shielding on said cables and said housing.

4. A combination comprising: a distributor including a grounded flangedbase and a distributor head adapted to be supported concentricallythereon, a mounting ring of high conductive properties secured upon theybase, means upon the mounting ring adapted to releasably clamp thedistributor head upon the said ring, an inverted cup-shaped housing ofhigh conductive properties secured upon the mounting ring with its wallspaced from the distributor head, and cable terminals leading throughsaid housing to the distributor head and establishing an electricalconnection between metal shielding on said cables and said housing.

ALFRED HALLE'IT.

